Recently, in a vehicle, an air bag device, which is one of a safety device, has become a standard equipment in order to ensure safety of an occupant in case of a traffic accident. An impact generated on the vehicle by a collision is detected by a G-sensor. Based on a signal from the G-sensor, an operating signal for operating the air bag device is inputted to the air bag device which is provided in the center of a steering wheel for a driver or a dashboard panel of a passenger seat. When the operating signal is inputted to the air bag device, an inflator accommodated in the air bag device is ignited. By this ignition, gas for inflating the air bag is expanded. Then the air bag is quickly inflated by the gas, and the occupant sitting on a front seat is protected.
When the air bag device has to be accurately controlled, a type of the occupant sitting on the seat (“adult”, “child”, or “no occupant”) needs to be determined accurately. For example, a known occupant weight detecting device is disclosed in a Japanese Patent Laid-Open Publication No. 9-207638. The occupant weight detecting device has four load detecting sensors for detecting weight of an occupant sitting on a seat. Based on output load values detected by the four load detecting sensors, load detection value is calculated by CPU. Then the type of the occupant sitting on the seat is determined by comparing the load detection value with each predetermined threshold.
However, in the occupant weight detecting device disclosed in the foregoing publication, the occupant determination transaction is performed according to a program including plural subroutines, and accordingly the program becomes long and complicated. This longer and complicated program is not preferable since this may allow a coding error and a bug.
The present invention therefore seeks to provide an occupant weight detecting device transacted by a relatively shorter program for determining a type of an occupant than a conventional program and preventing generation of a coding error and a bug.